AbstractTo evaluate the prevalence of aortic regurgitation (AR) and associations between the individual aortic root components and AR severity in the general population. The study included the first 10,000 participants of the population-based Hamburg City Health Study (HCHS) of whom 8259 subjects, aged 62.23 ± 8.46 years (51.3% females), enrolled 2016–2018, provided echocardiographic data. 69 subjects with bicuspid valves and 23 subjects with moderate/severe aortic stenosis were excluded. Aortic root dimensions were measured using state-of-the-art cardiac ultrasound, including the aortic annulus, sinus of Valsalva, sinotubular junction (STJ), and ascending aorta, in diastole and systole. The distribution of AR was: 932 (11.4%) mild, 208 (2.5%) moderate, and 20 (0.24%) severe. Patients with moderate or severe AR were predominantly male at advanced age who had hypertension, coronary artery disease, atrial fibrillation, and renal dysfunction. Increasing AR severity correlated with higher absolute and indexed aortic root diameters (e.g., end-diastolic sinus of Valsalva for no-mild-moderate-severe AR in mm ± standard deviation: 34.06 ± 3.81; 35.65 ± 4.13; 36.13 ± 4.74; 39.67 ± 4.61; p < 0.001). In binary logistic regression analysis, all aortic root components showed significant associations with moderate/severe AR. Mid-systolic STJ showed the strongest association with moderate/severe AR (OR 1.33, 95% confidence interval 1.25–1.43, p < 0.001). AR was prevalent in 14.2%, of whom 2.8% showed moderate/severe AR. All assessed aortic root diameters correlated with the prevalence and severity of AR. STJ diameter had the strongest association with moderate/severe AR possibly reflecting the pathophysiological impact of an increasingly dilated STJ in the context of an ageing aorta.